1. Field of the Invention
The present invention relates to a method and apparatus for polishing a wafer, and more particularly to a method for polishing a wafer for an extended effective area of the wafer, and an apparatus for the same.
2. Description of the Related Art
As a method for polishing a wafer is known the technique described in, For example, Japanese Laid Open Patent Application (JP-A-Heisei 5-326468). In the above conventional example, as shown in FIGS. 1A and 1B, the circumference ring 35, which is thinner than the thickness of a wafer 36, is provided around the wafer 36. The wafer 36 surrounded by the circumference ring 35 is mounted on a carrier 31, and the carrier 31 is pushed to a polishing pad section 32 which is mounted on a polishing table 33, while the carrier 31 and the polishing table 33 are rotated. As a result, the wafer 36 is polished.
In the above conventional example, the wafer 36 is pushed to the polishing pad section 32. Therefore, in case of polishing, a great load is imposed on a peripheral portion of the wafer 36, because the wafer 36 protrudes out of the circumference ring 35. As a result, the polishing rate becomes large in the peripheral portion of the wafer, so that uniformity of the wafer surface is not obtained.